Bow tie methodology description of examples
Updated 10 February 2015
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Introduction
Four bow tie examples have been generated thus far by the Military Aviation Authority. They focus on:
- mid-air collision
- controlled flight into terrain
- fire/explosion
- runway incursion
- runway excursion
They have been generated using internal MAA subject matter expert (SME) resources from across the aircrew, engineering and air traffic management (ATM) domains. It is stressed that the bow ties shown are representative of work to date and not intended to provide a final solution to the issue addressed. Instead they aim to generate discussion, acting as a framework for review of assurance and mitigations.
Importantly, the bow ties are not constructed to represent MAA Regulatory Publications (MRP) compliance.
Series 1: Airprox/mid air collision (MAC)
| Description of a hazard | Description of a top event | Assumptions | Issue | Date | Diagram level 1 | Diagram level 2 |
|---|---|---|---|---|---|---|
| 2 or more aircraft in the vicinity of each other whilst airborne in UK Class G airspace | loss of safe separation between two aircraft | flights are authorised; remotely piloted air systems (RPAS) in airspace are effectively managed | 3 | February 2015 | hazard, top event, threats, outcomes and barriers | hazard, top event, threats, outcomes, barriers, escalation factors and barriers |
Series 2: Controlled flight into terrain (CFIT)
| Description of a hazard | Description of a top event | Assumptions | Issue | Date | Diagram level 1 | Diagram level 2 |
|---|---|---|---|---|---|---|
| military aircraft operating close to the surface (including surface based objects) | unintentional loss of authorised separation with the surface or an obstruction | ‘surface’ includes obstacle and terrain; ‘operating’ implies that the aircraft is under control which includes crew, aircraft and, as far a possible dependent on airspace, ATM; bow tie takes into account all flight phases from takeoff to approach excluding landing phase; hard/heavy landing is not classed as CFIT; planned landing as a result of an emergency is not included as this is not considered in control | 2 | November 2014 | hazard, top event, threats, outcomes and barriers | hazard, top event, threats, outcomes, barriers, escalation factors and barriers |
Series 3: Fire and explosion
| Description of a hazard | Description of a top event | Assumptions | Issue | Date | Diagram level 1 | Diagram level 2 |
|---|---|---|---|---|---|---|
| the aircraft is under control of the MRP; the event on aircraft includes a combustible substance and heat; atmospheric oxygen is present; maritime operations are included; the aircraft is allotted to the forward domain; combustion may result in fire, explosion, smoke and fumes or any combination thereof; a human presence is not necessarily required; excludes events resulting from enemy action; excludes post crash events | hazard, top event, threats, outcomes and barriers | hazard, top event, threats, outcomes, barriers, escalation factors and barriers |
Series 4: Runway incursion
| Description of a hazard | Description of a top event | Assumptions | Issue | Date | Diagram level 1 | Diagram level 2 |
|---|---|---|---|---|---|---|
| airfield and landing site operations | incorrect presence of entity on surface designated for take-off and landing operations | entity refers to any aircraft, vehicle, person or wildlife; we have decided to include FOD in this revised version | 2 | February 2015 | hazard, top event, threats, outcomes and barriers |
Series 5: Runway excursion
| Description of a hazard | Description of a top event | Assumptions | Issue | Date | Diagram level 1 | Diagram level 2 |
|---|---|---|---|---|---|---|
| take-off and landing operations | loss of control whilst in contact with the surface designated for take-off and landing operations | refers to an aircraft during the take-off or landing sequence that inadvertently departs from the surface designated for that purpose | 1 | February 2015 | hazard, top event, threats, outcomes and barriers |